Heat exchangers are well known in the art. By way of example, a conventional heat exchanger 2 is diagrammatically illustrated in FIG. 1 and is sometimes referred to as a “cooling tower”. The heat exchanger 2 includes a container 4, a direct heat exchanger device 6, a conventional cooling fluid distribution system 8, an air flow mechanism such as a fan assembly 10 and a controller 12. The container 4 has a top wall 4a, a bottom wall 4b and a plurality of side walls 4c. The plurality of side walls 4c are connected to each other and connected to the top wall 4a and the bottom wall 4b to form a generally box-shaped chamber 14. The chamber 14 has a water basin chamber portion 14a, an exit chamber portion 14b and a central chamber portion 14c. The water basin portion 14a is defined by the bottom wall 4b and lower portions of the side walls 4c. The water basin portion 14a contains cooled fluid as discussed in more detail below. The exit chamber portion 14b is defined by the top wall 4a and upper portions of the side walls 4c. The central chamber portion 14c is defined between and among central portions of the connected side walls 4c and is positioned between the water basin chamber portion 14a and the exit chamber portion 14b. The top wall 4a is formed with an air outlet 16. The air outlet 16 is in fluid communication with the exit chamber portion 14b. Also, for this particular conventional heat exchanger 2, each one of the side walls 4c is formed with an air inlet 18 in communication with the central chamber portion 14c. A plurality of louver modules 20 are mounted to the side walls 4c in the respective air inlets 18. The plurality of louver modules 20 are disposed adjacent to and above the water basin chamber portion 14a and are operative to permit ambient air, illustrated as Cold Air IN arrows, to enter into the central chamber portion 14c. 
The direct heat exchanger device 6 is disposed in and extends across the central chamber portion 14c adjacent to and below the exit chamber portion 14b. The direct heat exchanger device 6 is operative to convey a hot fluid, illustrated as a Hot Fluid IN arrow, therethrough from a hot fluid source 22. It would be appreciated by a skilled artisan that the hot fluid is typically water but it might be some other liquid fluid. The hot fluid exits the direct heat exchanger device 6 as cooled fluid, illustrated as a Cooled Fluid OUT arrow. Although the direct heat exchanger device 6 is diagrammatically illustrated as a film fill material structure, a skilled artisan would comprehend that the direct heat exchanger device 6 can be any other conventional direct heat exchanger device such as a splash bar or splash deck structure.
The cooling fluid distribution system 8 includes a fluid distribution manifold 24 that extends across the central chamber portion 14c and is disposed above and adjacent to the direct heat exchanger device 6. In a Pump ON state, a pump 26 is operative for pumping the hot fluid illustrated as a Hot Fluid IN arrow from the hot fluid source 22 to and through the fluid distribution manifold 24. Thus, the hot fluid illustrated as a Hot Fluid IN arrow is distributed onto the direct heat exchanger device 6 as represented by the water droplets 28 in FIG. 1. When the water droplets 28 rain downwardly onto the direct heat exchanger device 6 and into the water basin chamber portion 14a, the conventional heat exchanger 2 is considered to be in a WET mode. The water droplets 28 accumulate in the water basin chamber portion 14a as the cooled fluid, which is usually pumped back to the hot fluid source 22 represented by the Cooled Fluid OUT arrow.
As illustrated in FIG. 1, the cooling fluid distribution system 8 includes a plurality of spray nozzles 30. The spray nozzles 30 are connected to and are in fluid communication with the fluid distribution manifold 24 so that the pump 26 pumps the hot fluid from the hot fluid source 22, to the fluid distribution manifold 24 and through the spray nozzles 30. However, one of ordinary skill in the art would appreciate that in lieu of the cooling fluid distribution system 8 that includes spray nozzles 30, the cooling fluid distribution system 8 might include a weir arrangement, a drip arrangement or some other conventional fluid distribution arrangement with or without spray nozzles.
Furthermore, in FIG. 1, the heat exchanger 2 includes an eliminator structure 32 that extends across the chamber 14 and is disposed between the fluid distribution manifold 24 and the air outlet 16. The eliminator structure 32 is positioned in a manner such that the exit chamber portion 14b of the chamber 14 is disposed above the eliminator structure 32 and the central chamber portion 14c of the chamber 14 is disposed below the eliminator structure 32.
In a Fan ON state shown in FIG. 1, the fan assembly 10 is operative for causing the ambient air represented by the Cold Air IN arrows to flow through the heat exchanger 2 from the air inlet 18, across the direct heat exchanger device 6 and the fluid distribution manifold 24 and through the air outlet 16. As shown in FIG. 1, in the WET mode, hot humid air represented by Hot Humid Air Out arrow flows out of the air outlet 16. As known in the art, the fan assembly 10 shown in FIGS. 1 and 2 is an induced draft system to induce the ambient air to flow through the container 4 as illustrated.
The controller 12 is operative to selectively energize or de-energize the cooling fluid distribution system 8 and the fan assembly 10 by automatically or manually switching the cooling fluid distribution system 8 and the fan assembly 10 between their respective ON states and an OFF states in order to cause the heat exchanger 2 to operate in either the WET mode or an OFF mode (not illustrated). The controller 12 might be an electro-mechanical device, a software-operated electronic device or even a human operator. For the heat exchanger 2 to be in the OFF mode, i.e., in an inoperative mode, the controller 12 switches the fan assembly 10 to the Fan OFF state and switches the pump 26 to the Pump OFF state. In FIG. 1, for the heat exchanger 2 to be in the WET mode, the controller 12 switches the fan assembly 10 to the Fan ON state and switches the pump 26 to the Pump ON state. More particularly, in the WET mode, both the fan assembly 10 and the cooling fluid distribution system 8 are energized resulting in the ambient air (Cold Air IN arrows) flowing through the direct heat exchanger device 6 and the hot fluid being distributed onto and across the direct heat exchanger device 6 to generate the hot humid air (Hot Humid Air OUT arrow in FIG. 1) that exits through the air outlet 16.
Throughout the year, the heat exchanger 2 operates in the WET mode. Sometimes, during the spring, fall and winter months, the ambient conditions cause the hot humid air that exits the heat exchanger to condense, thereby forming a visible plume P of water condensate. Occasionally, the general public mistakenly perceives this visible plume P of water condensate as polluting smoke. Also, some people, who know that this plume P is merely water condensate, believe that the minute water droplets that constitute the visible plume P might contain disease-causing bacteria. As a result, a heat exchanger that spews a visible plume P of water condensate is undesirable.
There are two limitations on heat exchangers that the present invention addresses. First, particularly in cold climates, cooling towers can emit plume when the warm, humid air being discharged from the unit meets the cold, dry air in the ambient environment. The general public sometimes mistakenly perceives this visible plume of water condensate as air-polluting smoke. Second, water is considered to be a scarce and valuable resource in certain regions. In certain aspects of the present invention, there is an increased capacity to perform the cooling functions in a DRY mode, where little or no water is needed to achieve the cooling function.
A skilled artisan would appreciate that the diagrammatical views provided herein are representative drawing figures that represent either a single heat exchanger as described herein or a bank of heat exchangers.
It would be beneficial to provide a heat exchanger that conserves water. It would also be beneficial to provide a heat exchanger apparatus that might also inhibit the formation of a plume of water condensate. The present invention provides these benefits.